Fastening means for turbine blading



June 29, 1926.

, J. E SNYDER FASTENING MEANS FOR TURBINE BLADIEJG Filed August 13, 15323 mvsmore qatente cl June 29, 1926.

UNITED STATES PATENT OFFICE.

JOHN E. SNYDER, on PHILADELP IA, PEN sYLvaNra, ASSIGNOR To wnsrrnenousn nnncrnrc AND MANUFACTURING COMPANY, A conronarron on PENNSYLVANIA.

, FASTENING MEANS For. TURBINE BLADING.

Application filed August 13, 1923. Serial N0. 657,029.

My invention relates to fastening means for turbine blades and it has for its object to provide apparatus for quickly and securely assembling a blade Structure and which shall substantially preclude subse quent movement of the blades relative to the supporting member.

In the accompanying drawing, Fig. 1 is a perspective view of a turbine blade constructed in accordance with a preferred form of my invention; Fig. 2 is a plan View, partially in section and partially in elevation, of a portion of a blade holding member with two blades and the associated packing piece disposed therein; Fig. 3 is a perspective view of a packing piece suitable for use in the structure of Fig. 2; Fig. 4 is a perspective view of a blade with the packing piece of Fig. 3 placed thereagainst and fastened in place as by welding; and Fig. 5 is a View similar to Fig. 2 and illustrating a modified form of my invention.

In the mounting of turbine blades, it has been usual to provide the. blade supporting member with an undercut groove or slot, and to cause the blades to engage in said slot as by a suitably formed root. Packing pieces are disposed between the blades to maintain the appropriate spacing therebetween.

l/Vhile this structure has in general been entirely satisfactory, nevertheless, at times, there has been a slight tendency to lateral movement of the blade with respect to the packing piece or, in other words, a skewing of the blade about its longitudinal axis.

My invention is directed specifically tothe prevention of such action and, to this end, I provide the blades and packing pieces with interlocking portions, such as grooves and lugs, whereby relative lateral motion thereof is precluded.

Referring to the drawing for a more detailed understanding of my invention, I show a portion of a turbine blade holding structure at 10 in Fig. 2, this structure being provided with a groove 11 having undercut portions 12 and 13.

Blades 14 are provided with upset root portions 15 adapted to project within the groove 11, and a packing piece as shown at 16 is placed between each adjacent pair of blades. The packing piece is provided with beveled end faces as shown at 17 in Fig. 8, for engagement with the undercut portions 12 and 13 of the slot 11. The packing piece 1'? overlying the lug 15 securely holds the blade-s in position.

.In order to prevent lateral displacement ofthe blades with respect to the packing pieces, with resultant harmful alteration of the entrance and exit angles, as might well happen were the slot slightlytoo wide for the blade, I show the packing piece as provided with protuberances 1818 on the concave face thereof,.and as provide-d with grooves or depressions 1919 on the convex' face thereof, complementary lugs and grooves being provided on the respective blades so that, when the assembly is made, a definite interlocking action is established between each blade and its immediately associated packing pieces. In Fig. 1, I show lugs 2020 on the concave face of a blade and a slot at 21 on the convex face thereof for achieving this purpose.

Obviously I may omit the interlocking action on one face of each blade, relying entirely on engagement between members on the other face of said blade and the adjacent packing piece. Similarly, I may, if desired, interchange the members as by forming lugs on the convex face of the blade with complemental grooves or depressions on the concave face of the packing piece.

In the form of my invention shown in Fig. i, an even more rigid structure is formed by welding or brazing a packing piece'16 directly to a bladelt, at the same time providing the concave face of the packing piece with suitable lugs 18'-18 for engagement with complemental. depressions in the adjacent blade. By the provision of locking lugs and grooves 1919, accurate registry of a blade and of its associated packing piece is provided prior to and during the welding operation, whereby the welding may be done rapidly and yet accurately.

Inasmuch as it is more feasible to mill out a depression on a member than to form a lug thereupon, I may, if desired, employ the structure shown in Fig. 5 wherein blades 1414 embrace a packing piece 16", all three members being provided with grooves in which are driven, or placed, suitable locking pins or members 2222, thus providing the desired locking action.

While I have shown my invention in but three forms, it will be obvious to those skilled 'ber provided with a blade-holding slot, of 'a v turbine blade having depressions extending lengthwise of theblade on the-convex sides of the root portion thereof, and packing pieces arranged between the blades and having lugs on the concave 'si le thereof to fitsaid depressions. l

'2. The combination with a turbine member provided with a blade-holdingslot, of a turbine blade having depressions extending lengthwise of the blade on theconvex sides of the root portion thereof,;and packing pieces arranged between the blades and having lugs on the concave side thereof to fit said depressions, said packing pieces being secured to the convex side of the blade.

3; The combination With a turbine blade, of a packing piece autogenously attached thereto, said members being provided with interlocking meansextending lengthwise of the blade whereby they are maintained in predetermined registry during the attaching operation.

4. The combination with a turbine blade provided with a laterally-extending root portion, of a packing piece overlying said -1'oot portion and being autogenously attached to said blade, said blade and said packing piece being provided with interlocking portions, whereby they are held in accurate predetermined registry'during the attaching operation. l a

In testimony whereof, I have hereunto subscribed my name this 2nd day of Aug. 1923. r

' JOHN E. SNYDER. 

